1. Field of the Invention
The present invention relates to management of digital content, and in particular, to systems and methods for providing protected digital content to authorized users.
2. Description of Related Art
Piracy is a significant concern among digital content providers. With the ubiquity of high speed Internet connectivity, transfers and downloads of even high definition quality movies can easily and rapidly be accomplished over networks. Moreover, the electronic delivery of digital content removes several barriers to pirating. One barrier that is removed is any requirement for the user to purchase a tangible article, such as CD and DVD disks, containing the digital content. Another barrier is the digital format of the content itself. Because there is no degradation in quality of copied digital content, there is no perceived disadvantage to using original versus pirated digital content. Copyrighted digital content of all types is regularly pirated on a massive scale, demonstrating the failure of present technology to prevent unauthorized copying.
Digital content providers have responded to the threat of digital piracy by implementing various strategies to discourage or prevent unauthorized access and copying. One such strategy is to provide incentives for consumers to purchase original DVD disks by including value-added content that is not otherwise available to the public. The problem persists, however, in that the original DVD disks themselves can be pirated. To that end, a copy protection requirement, known as the content scrambling system (CSS), is implemented in the DVD standards to prevent unauthorized copying of video files directly from the disc. CSS accomplishes this by scrambling certain sectors containing audio-video data in such a way that the data cannot be used to recreate a valid signal. The scrambled sectors are encrypted with a title key stored in the sector header and a disc key which is hidden in the control area of the disc and is not directly accessible.
The CSS algorithm and keys were supposed to remain secret, but in 2000, computer hackers were able to reverse engineer the algorithm and derive all of the keys. Still, CSS and other content-protection schemes for DVD, Blu-Ray, and other digital media often prevent the average user from using a computer to copy a DVD movie or other digital content, and perfect unauthorized DVD copies are rare or non-existent. Instead, many pirated copies of DVD's are generated using what is sometimes referred to as the “analog hole” to create digital copies from the analog output of a player device. Even digital pirated copies can often be detected by small differences in digital data that may or may not affect the copies' playability and analog output. Absolute content protection is perhaps unrealistic, as a completely foolproof copy protection method would make it impossible to use the disc. If you can see it or hear it, you can copy it. There is therefore a need for digital content providers to be able to provide a more secure distribution system for digital content that protects the rights of content owners by further encouraging customers to purchase original authorized copies of content and provides greater copyright protection for downloadable content.